Is there any intron sliding in mammals?

Area of Science:

• Genomics
• Evolutionary Biology
• Molecular Biology

Background:

• Eukaryotic genes contain exons and introns, with conserved exon-intron boundaries across species.
• Intron sliding, a debated phenomenon involving short-distance intron relocation, is challenging to detect.
• Accurate genome annotations and high-quality transcriptome data are crucial for identifying intron sliding events.

Purpose of the Study:

• To investigate the presence or absence of intron sliding in mammals.
• To expand knowledge regarding intron sliding phenomena within this taxonomic group.

Main Methods:

• Utilized highly accurate genome annotations and genome sequences.
• Employed high-quality transcriptome data for analysis.
• Examined intron sliding events in primate and other mammalian gene orthologs.

Main Results:

• No significant evidence of intron sliding was found in the primate group (including human, chimpanzee, and various macaques).
• A single potential intron sliding event was observed between human and sheep EIF1AX gene orthologs, supported by high-quality transcriptomes.
• Previously reported mammalian intron sliding events were largely identified as artifacts of genome annotation, lacking support from transcriptomic data or subsequent annotation versions.

Conclusions:

• Intron sliding is considered an exceedingly rare evolutionary event, if it occurs at all.
• Confirmation of intron sliding requires extensive supporting data due to its elusive nature.